MEDIUM CVSS 5.0
Published: 2026-06-09

CVE-2026-11787

redhat directory_server Security Advisory (CVE-2026-11787)
↗ Official NIST NVD Record
Seeking technical exploit breakdowns or verified PoC code for CVE-2026-11787?
🔬 Search Writeups & Exploit Archive →

CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-11787 impacting redhat directory_server. Evaluated with CVSS Base Score of 5.0 (MEDIUM).

Original NVD Description

Source: NIST NVD
A flaw was found in 389 Directory Server. The ldap_utf8prev() function reads bytes before the start of a buffer without bounds checking, causing a heap buffer over-read in string filter parsing that may influence internal filter processing behavior.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
High (AC:H)
Depends on race conditions or environment
Privileges Required
Low (PR:L)
Standard user access required
User Interaction
None (UI:N)
Zero human interaction required
Scope
Unchanged (S:U)
Confined to same security context
Confidentiality
Low (C:L)
Partial information leakage
Integrity
Low (I:L)
Partial data modification possible
Availability
Low (A:L)
Partial service performance degradation

🎯 Affected Versions Matrix

Affected Product redhat / directory_server
Affected Versions 11.0
Weakness Enumeration CWE-126

Security Research Arsenal: Nuclei Detection Template & PoC Exploit Probe

High-Intent Research Tool

Ready-to-use security scanner signatures, active verification probe skeletons, and remediation playbooks for CVE-2026-11787 impacting redhat directory_server.

⚡ Nuclei Detection Template (YAML) cve-2026-11787.yaml
id: cve-2026-11787

info:
  name: redhat directory_server - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-11787 affecting redhat directory_server.
    Evaluation: A flaw was found in 389 Directory Server. The ldap_utf8prev() function reads bytes before the start of a buffer without bounds checking, causing a hea...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-11787
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
    cvss-score: 5.0
    cve-id: CVE-2026-11787
    cwe-id: CWE-126
  tags: cve,cve-2026-11787,redhat,directory_server,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "directory_server"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-11787.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-11787
# Target: redhat directory_server | CVSS: 5.0 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-11787 (redhat directory_server)...")
    headers = {
        "User-Agent": "CyberVault-Audit-Scanner/2.0",
        "Accept": "*/*"
    }
    try:
        r = requests.get(f"{target_url.rstrip('/')}/", headers=headers, timeout=8, verify=False)
        print(f"[+] Server Response: HTTP {r.status_code} | Server Banner: {r.headers.get('Server', 'Unknown')}")
        if r.status_code < 500:
            print(f"[!] Target reachable. Verify version against redhat directory_server scope (11.0).")
        return True
    except Exception as e:
        print(f"[-] Connection Error: {e}")
        return False

if __name__ == '__main__':
    url = sys.argv[1] if len(sys.argv) > 1 else "http://localhost:8080"
    verify_vulnerability(url)
🛡️ Quick Patch & Remediation Script (Bash) patch_cve-2026-11787.sh
# Recommended Remediation & Patching Commands for CVE-2026-11787
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install directory_server 2>/dev/null || \
sudo dnf upgrade directory_server 2>/dev/null || \
sudo yum update directory_server

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i directory_server 2>/dev/null || rpm -qa | grep -i directory_server

# 3. Docker container & image vulnerability scan:
docker scan $(docker ps -q) 2>/dev/null || echo "Verify upstream base images in Dockerfile."

🛡️ Remediation & Security Action

  • Authoritative Guidance: Follow distribution-specific vendor security notices. Advisory status and package patches vary by distribution release.
  • Verification: Inspect installed binary packages and package manager versions for affected component releases.
  • Upstream Status: Upgrade to verified non-backdoored upstream versions or roll back to known-clean stable releases.
⚠️ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

🔗 Verified Technical References

Authorities
  • No records filed in this category.
Technical Analysis
  • No records filed in this category.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-11787 in redhat directory_server?

Review vendor-specific security notices and update redhat directory_server packages to the latest patched release immediately. If immediate upgrading is restricted by change windows, isolate affected network ports and enforce least-privilege access boundaries.

Is there an active exploit or public PoC for CVE-2026-11787?

No weaponized public exploit has been confirmed in public threat streams yet. Continuous surveillance is active across GitHub and security feeds.

What is the CVSS 3.1 severity rating and impact for CVE-2026-11787?

CVE-2026-11787 is classified with a CVSS 3.1 Base Score of 5.0 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
5.0
MEDIUM SEVERITY
CVE ID CVE-2026-11787
Weakness CWE-126
Vendor redhat
Product directory_server
Published 2026-06-09
Vector CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L